I took your advice and just went ahead with the 570 as well as your other recommendations. I just really wanted to say thank you for all your help! I finally got everything installed and got Innerspace / ISBoxer running and man it's smooth as silk.

I'm only running two accounts at the moment while I test out my key mapping / binding set up. (I want to do a test case before I sit down and basically do 480 key maps.) But it's obvious I've got more than enough juice to handle four. Thanks again for all your help!

-Moo!